Just a little after a year of getting marketing approval for restless leg syndrome in the United States, Horizant, co-developed by Xenoport Inc. (XNPT) and GlaxoSmithKline plc (GSK), now awaits the regulatory decision for yet another indication, which is scheduled to be announced in two weeks.
For readers who are new to Xenoport, here's a brief overview of the upcoming events...
Horizant Extended-Release Tablet , whose chemical name is gabapentin enacarbil, is under FDA review for a new indication namely, management of postherpetic neuralgia in adults. Postherpetic neuralgia, or PHN, is the most common complication of shingles, and is characterized by persisting nerve pain that lasts for over a month. Shingles is caused by varicella-zoster virus - the same virus that causes chickenpox.
The first oral medication approved by the FDA for PHN is Pfizer Inc.'s (PFE) Neurontin that was given the green signal in 2002. NeurogesX Inc.'s (NGSX) Qutenza (capsaicin) 8% patch, a dermal delivery system , is also an FDA-approved product for the management of neuropathic pain due to PHN.
Xenoport, which discovered and developed Horizant, inked an agreement with GlaxoSmithKline in 2007, to co-develop and commercialise the drug in the U.S. The drug was approved by the FDA last April for restless legs syndrome, a neurological disorder characterized by an urge to move the legs, usually caused by or accompanied by uncomfortable and unpleasant sensations in the legs. The drug was commercially launched for that indication in the United States by GlaxoSmithKline in July of 2011.
The following month that year - August 2011, GlaxoSmithKline submitted a supplemental New Drug Application seeking approval of Horizant for the management of postherpetic neuralgia in adults. The sNDA, which was accepted by the FDA, has a decision date set for June 9, 2012. The FDA's acceptance of the sNDA triggered a milestone payment to XenoPort of $5.0 million.
The exclusive rights to develop and commercialize gabapentin enacarbil in Japan, Korea, the Philippines, Indonesia, Thailand and Taiwan, rest with Astellas Pharma Inc. In February of this year, gabapentin enacarbil was approved under the brand name Regnite in Japan that fetched a $10 million milestone payment for Xenoport from Astellas.
Shares of Xenoport have thus far hit a 52-week low of $3.46 and 52-week high of $8.07. The stock closed Thursday's trading at $5.88, up 0.17%. As the regulatory decision date nears, it will be interesting to watch how the stock plays out. Stay tuned...
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April 24, 2026 15:15 ET Economics news flow was relatively light this week even as the conflict in the Middle East continued, raising concerns for policymakers. In the U.S., spending data, initial jobless claims and pending home sales were the highlights. Business confidence in the biggest euro area economy was in focus in Europe. Inflation data from Japan gained attention in Asia.